While the present invention was developed for use in the railroad industry, and is described in this environment, it is to be understood that the invention can be used in other environments where it is necessary to provide a high efficiency marker light that forms a solid cone-shaped beam path that can be constructed and operated at low cost. More particularly, the present invention is ideally suited to applications where such a marker light must efficiently use a limited supply of electrical energy.
High visibility marker lights are used in the railroad industry as warnings of obstructions to train engineers. Typically, these marker lights are installed on the last car of a train to warn engineers in oncoming trains of the presence of a preceding train on the track.
Because trains travel at high rates of speed, and because regulations in many countries frequently require the rear marker lights of trains to be red, red-orange, or some variation thereof, the marker light must be sufficiently bright to be seen at a great distance in order to permit the engineer of an oncoming train to slow the train down in time. In addition, because many railroad tracks pass over hilly terrain, the rear marker light must project a solid cone of light of sufficient brightness along a beam path wide enough and tall enough to be visible to oncoming trains around curves, as well as at the crest of hills or in the troughs of valleys. To permit extended use when powered by batteries, these lights must use minimum energy to produce the requisite beam pattern and brightness. Consequently, there is a need for a high visibility marker light that meets the aforementioned requirements.